After posting the photo she copped criticism from trolls as well as a number of media outlets claiming she was going against doctors advice exercising so soon.
Bec however was quick to put them al in their place, amending the caption: "Yes, of course we checked with obstetrician first. Thanks for caring sooooo much Daily Mail".
While six weeks is the general recommendation, everybody is different and everybody has different levels of fitness and recovery, so as Bec says, it's always best to consult your doctor.
Last weekend the new mum headed out to Derby Day where she spoke about being a mother of four and how she is feeling.
"It still has not sunk in that I am a mum of four," she told the Daily Telegraph.
"I am feeling really good. I have got a lot of experience under my belt now, so I am glad I had my twins last and not first up."
The model and TV presenter said it was nice to have a day out and get glammed up after weeks of being in the house in "baby mode".
"I went and had my hair and make-up done, put on a dress and am feeling almost like my old self again. I have just been in baby mode. They are my last newborns. I am never going to go through this again, so I am just trying to not rush it, not rush getting back into work, and live in the moment and enjoy my babies.’’